Re: update only if single row
От | Moray McConnachie |
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Тема | Re: update only if single row |
Дата | |
Msg-id | 006001bfa06d$d45f5480$760e01a3@oucs.ox.ac.uk обсуждение исходный текст |
Ответ на | update only if single row (Frank Bax <fbax@execulink.com>) |
Список | pgsql-sql |
> select * from contact where email ~* 'rvro'; > if I get a single row in the result then I enter: > update contact set bounce=1 where email ~* 'rvro'; > > Can I combine this into a single SQL statement with the following > requirements: > 1) the update is only performed if a single row is selected > 2) I only enter the selection string ('rvro' in this case) once in the If you have some kind of id field in the table, you can do it like this, or you can use the oids, but I don't know how to write that :-> I'm not quite sure that the aliasing works properly in this query either - does the EXISTS clause pick up the a alias? UPDATE contact a SET a.bounce=1 WHERE a.email ~* 'rvro' AND NOT EXISTS (SELECT id FROM contact b WHERE b.email ~*'rvro' AND a.id !=b.id); Yours, Moray
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